KR20220109197A - Electric Vehicle Charging Device - Google Patents

Abstract

The present invention relates to an electric vehicle charging device which comprises: an outer connector connected to an electric vehicle of a user; and a relay mesh supplying power to the outer connector. An output power amount supplied through the relay mesh according to selection between rapid charging or slow charging by a user can be varied. The relay mesh can comprise an SiC module. The SiC module comprises: an SiC MOSFET module acting as a switch function of electricity supplied to the outer connector; and an SiC drive module transmitting a driving signal for switching to the SiC MOSFET module.

Description

Electric Vehicle Charging Device

The present invention relates to an electric vehicle charging device for charging an electric vehicle using a SiC MOSFET.

As a part of green technology development, a lot of research on a charging system for an electric vehicle is being conducted in order to increase the utility of the electric vehicle as well as research on the electric vehicle. However, since it is still in the development stage, a charging system that meets various consumer needs as well as technical problems to be solved has not been popularized.

For mass distribution of electric vehicles, it is necessary to narrow a relatively long charging time to the fueling time of vehicles using fossil fuels.

The present invention is a charging device for high-speed charging of an electric vehicle, and may include a silicon carbide-based MOSFET device capable of high-speed switching even at high power and high voltage.

The present invention is an electric vehicle charging device, comprising an external connector connected to the user's electric vehicle, and a relay mesh for supplying electricity to the external connector, and the amount of output power supplied through the relay mesh according to the user's selection of fast charging or slow charging This can be variable.

The relay mesh may include a SiC module, and the SiC module may be provided with a SiC MOSFET module serving as a switch for electricity supplied to the external connector, and a SiC drive module that sends a driving signal for switching to the SiC MOSFET module. have.

The SiC drive module may be equipped with a digital isolator that physically separates the SiC drive module from other circuits, and a charge pump serving as a DC-DC converter.

The SiC MOSFET module includes a heat sink that lowers heat loss generated from the SiC MOSFET module, a power connector to which electricity supplied to the external connector is connected, and is turned on when electricity is supplied to the external connector, and is turned on when not supplied. A SiC MOSFET that is turned off may be provided, and the SiC MOSFET may use silicon carbide (SiC) as a material of a semiconductor device.

A display unit may be provided for a user to select rapid charging or slow charging, a signal according to the user's selection may be sent to a control board, and the control board may send an operation signal to the external connector and control unit selected by the user. In addition, the control unit may control the amount of power transmitted to the external connector by sending a trigger signal to the relay mesh according to the operation signal.

A first SiC module or a second SiC module may be provided in the relay mesh, and a power pack for supplying DC electricity for an electric vehicle to the first SiC module or the second SiC module is provided, and the first SiC module or the second SiC module is Array SiC modules connected in parallel are provided, and the array SiC module outputs an integer multiple of the amount of power output from the first SiC module or the second SiC module to the external connector according to a trigger signal from the control unit, and the integer is positive It may be a natural number.

Compared to Si IGBTs, SiC MOSFETs can have lower switching losses at higher temperatures, which in turn can reach higher switching scans, resulting in a compact circuit as a whole. In addition, since the SiC MOSFET has high heat resistance, the on-resistance can be maintained almost constant as the temperature rises.

Accordingly, the electric vehicle charging device of the present invention includes a SiC MOSFET device based on a silicon carbide material, so that it can be charged faster than the current Si-based MOSFET or IBGT module. You can choose.

The fourth SiC MOSFET may be a spare SiC MOSFET of the first power pack, and the third SiC MOSFET may be a spare SiC MOSFET of the second power pack.

1 shows a first SiC module or a second SiC module of the present invention.
2 shows an array SiC module of the present invention.
3 shows a SiC drive module of the present invention.
4 shows a SiC MOSFET module of the present invention.
5 shows an electric vehicle charging device of the present invention.
FIG. 6 is an enlarged view of part A of FIG. 5 .

For charging an electric vehicle (EV), most silicon (Si)-based MOSFETs (Metal Oxide Semiconductor Field-Effect Transistors) or insulated gate bipolar transistors (IGBTs) can be used.

However, rapid charging is required for mass dissemination of electric vehicles, and for this, a device capable of high-power and high-voltage high-speed switching is required.

To this end, it is necessary to utilize new materials to overcome the limitations of silicon devices using new materials. Such new materials may include gallium arsenide (GaAs), gallium nitride (gallium nitride, GaN), silicon carbide (SiC), and the like, which are compounds composed of gallium and arsenic. Among these new materials, a device using silicon carbide (SiC) can be used recently.

SiC bonds with Si and C in a 1:1 ratio, has a very strong bonding force, and can be thermally, mechanically, and chemically stable. In addition, compared to the IGBT module using Si, the SiC module 200 based on SiC can significantly reduce unnecessary energy loss occurring during power switching. In addition, the SiC module 200 may be miniaturized due to low resistance, thereby reducing the size of peripheral components, and a cooling mechanism such as the heat sink 420 may be simplified.

In the photovoltaic or electric vehicle industry, it is easier to be exposed to high voltage, high current, high power, and high temperature environments than existing industries, and it is desirable to apply a material capable of stably high-speed switching even in such an environment.

The bandgap can be divided into conductors, insulators, and semiconductors, and the bandgap between the energy band, the conduction band and the valence band.

When the Fermi level (Fermi energy), where electrons can stay with a 50% probability, approaches the conduction band, electrons move more easily inside the semiconductor and the semiconductor behaves like a conductor. When the Fermi level approaches the valence band, holes move inside the semiconductor. It is easy to do so the semiconductor can behave like an insulator. At this time, the Fermi level may move to one of the energy bands under the influence of an external electric field, heat, and the like, and the width of the band gap may also be reduced by heat. Therefore, when silicon is exposed to a high voltage, high current, high power, high temperature environment, etc., silicon having a small band gap tends to become unstable, and thus a material having a wide band gap stable even at high temperature or the like may be required.

Silicon carbide (SiC) has a bandgap three times wider than that of silicon, and may have less influence on electrons and bandgap changes due to heat. In addition, SiC has a critical field, which means the strength of the voltage that the material can withstand, about 10 times that of silicon, so it can operate without destroying the device at high voltage, and electron saturation is about 2 times faster than silicon. Due to the saturation velocity, it can be easy to fabricate devices capable of high-frequency operation, and the thermal conductivity that can dissipate heat is about 5 times that of silicon, which makes it stable even in high-voltage or high-temperature environments. may be operable.

That is, the SiC MOSFET 410 can produce a lower switching loss even at a higher temperature than an IGBT, and thereby can reach a higher switching frequency, so that the entire circuit can be compact. In addition, the on-resistance of the SiC MOSFET 410 may be maintained almost constant as the temperature rises due to its unique heat resistance.

The on-resistance Rds(on) is the resistance flowing between the drain and the source of the MOSFET, that is, the resistance value between the drain and the source when the gate is on, and depends on the gate voltage. may vary. In general, when the gate voltage is high, the on-resistance value is low, and it can be increased as the voltage between D-S increases. In the MOSFET, power loss may be expressed as on-resistance, and as the on-resistance value is smaller, power loss during operation may be reduced.

Accordingly, the electric vehicle charging device of the present invention includes the SiC MOSFET 410 element based on a silicon carbide material, so that it can be rapidly charged faster than the current Si-based MOSFET or IBGT module. The user may select fast charging at an additional cost or slow charging at a relatively low cost according to the setting of the provided charging device.

Referring to FIG. 1 , the electric vehicle charging device of the present invention may include a SiC relay, which is a SiC drive module 300 that sends an on/off driving signal S30 to a SiC MOSFET (SiC drive). module) and a SiC MOSFET module 400 including a SiC MOSFET 410 . That is, the driving signal S30 may be sent from the SiC drive module 300 to the gate of the SiC MOSFET 410 .

Referring to FIG. 3 , the SiC drive module 300 may include a digital isolator 310 (Digital isolator) and a charge pump 320 (Charge pump).

Most of the isolators for isolation in circuits using direct current use galvanic isolation, which enable communication between sub-circuits in a specific circuit and prevent unwanted direct current from flowing in the middle. It may be a circuit design technique. It can protect users or low voltage circuits from high voltages. Galvanic isolation allows no current to flow between the two circuits, but allows electrical signals or power to travel. For galvanic isolation, a method such as capacitance, inductance, electromagnetic wave, light, sound, or mechanical may be used, and components for this may include a photocoupler, a transformer, a relay, a Hall sensor, and the like.

The digital isolator 310 of the present invention may be a digital isolator rather than a method using an LED and a photo transistor. Therefore, the response speed may be significantly faster than that using the LED. Of course, it is possible to protect the devices from external noise/surge. Since the present invention uses the SiC MOSFET 410 capable of high-frequency and high-speed switching, the SiC drive for controlling the SiC MOSFET 410 must also have a response speed suitable for it, so the digital isolator 310 can be used. The digital isolator 310 may perform a role similar to that of an opto-coupler, except that the high voltage, high frequency, etc. must be operated. An optocoupler is an optical coupler in which an LED and a phototransistor are combined in a device. Optocouplers can transmit electrical signals with light, which can be important for noise countermeasure circuits. When only enough voltage and current to turn on the LED inside is applied, the light reaches the phototransistor and the transistor is turned on. can

Digital isolators can send digital signals across galvanic isolation boundaries, and multiplexed digital channels can be easily obtained. Accordingly, although the digital isolator 310 is a relatively expensive technology, as a result, a circuit can be simply configured, and consequently, net cost can be saved.

Accordingly, the charging device may be a solid state relay (SSR) in which an internal circuit such as a control terminal and a load 500 terminal is isolated.

The charge pump 320 may be one of the DC-DC converters, and a charger may be used as an energy charge storage to raise or lower the voltage.

In order for the MOSFET to operate, a voltage must be applied to the gate, and a dedicated driver for the SiC MOSFET 410 operating at high voltage and high frequency must be used to prevent malfunction of the gate.

Two power sources may be required for the digital isolator 310 and the charge pump 320 for the SiC drive module 300 . The power source for the digital isolator 310 may be a voltage between 1.5V and 9V, and the power source for the charge pump 320 may be a voltage between 15V and 25V higher than the digital isolator 310, up to 110mA current can flow.

Referring to FIG. 4 , the SiC MOSFET module 400 may include a SiC MOSFET 410 , a heat sink 420 (heat sink), and a power connector 430 . The SiC MOSFET 410 may be a central switching element of the SiC module 200 . The voltage from the drain to the source can be up to 1200V, and the current can have up to 100A. The SiC drive module 300 may send a driving signal S30 to a gate of the SiC MOSFET 410 , and a ground level of the drive module may be connected to a source of the SiC MOSFET 410 .

The heat sink 420 may reduce heat loss caused by current from the drain to the source, and may be formed of a gas or a liquid depending on the surrounding environment.

The power connector 430 may have a high voltage potential connected to the drain and a low voltage potential connected to the source side.

When the SiC MOSFET 410 is on, it may operate like a switch. In order to turn on the MOSFET, a gate signal may be required. The gate signal may be generated by a microcontroller, microcontroller unit (MCU), microprocessor, or any control system based on a simple digital circuit.

The control unit 20 may send a trigger signal S10 to the digital isolator 310, and as the trigger signal S10 increases, the digital isolator 310 may send a signal to the charging pump circuit. As a result, the charge-fun pump can provide an output signal to the SiC MOSFET 410 . When the SiC MOSFET 410 receives the driving signal S30 from the SiC drive module 300 , the power connector 430 is connected, and a current may flow from the drain to the source. This may be referred to as a first SiC module or a second SiC module.

The trigger signal S10 may be sent from the control unit 20 to the SiC drive module 300 for switching the SiC MOSFET 410 , and the control unit 20 controls the driving operation of the SiC module 200 as a state signal S20 . can be known, and the status signal S20 may be transmitted from the SiC drive module 300 to the control unit 20 .

2 and 5 , the electric vehicle charging apparatus may connect the first SiC module or the second SiC module in parallel for higher current switching. This array SiC module has the same voltage as the specific high voltage of the first SiC module or the second SiC module, and can output various currents according to the combination of the first SiC module or the second SiC module through the relay mesh 100 . and, as a result, various power values can be output. Therefore, it is connected to the external connector through the relay mesh 100, and the user can select fast charging according to the purpose. In this case, the first SiC module or the second SiC module is connected in parallel to form an array SiC module. Fast charging may be possible. All SiC drive modules 300 may be driven by the same trigger signal S10 for consistent operation. For example, when three first SiC modules or two second SiC modules are connected in parallel and connected through an external connector, the sub-loop circuit may have a maximum voltage of 1200V and a maximum current of 300A, so that the first SiC module or the second SiC module may have a maximum current of 300A. Three times the current or power of a SiC module can charge an electric vehicle through an external connector.

The SiC MOSFET 410 in the relay mesh 100 may be provided with various specifications depending on the situation, but if it is composed of the same SiC MOSFET 410, the first SiC module or the second SiC module in parallel as described above By installing the SiC module, the relay mesh 100 including the array SiC MOSFET 410 may have an output value corresponding to an integer multiple of the output value of each SiC MOSFET 410 . The integer may be a positive natural number.

For example, for power distribution, the SiC MOSFET 410 may be turned on to connect one or two power packs 10 to the external connector 30 . This may be an embodiment of the array SiC module, and various combinations may be possible according to the user's selection of fast charging or slow charging. The power pack 10 may send a direct current that can be used by the electric vehicle, and may be charged to the vehicle through the external connector 30 according to the on/off of the SiC MOSFET 410 . For example, the power pack 10 may be a DC power source having 30 kW.

When the user selects the amount of charge and the specific external connector 30 through the display unit 40, the control unit 20 through the control board 32 connected to the external connector 30 responds to commands such as fast charging or slow charging. Accordingly, it is possible to send a trigger signal S10 to the SiC module, and through this, the SiC drive module 300 sends a driving signal S30 to the SiC MOSFET module 400 so that the SiC MOSFET 410 operates on/off. As a result, the electric vehicle can be charged through the external connector 30 by the combination of the power of the power pack 10 connected to each SiC MOSFET 410 through the relay mesh 100 .

6 is an enlarged view of part A of FIG. 5 , a plurality of SiC modules may be provided in the relay mesh 100 , and FIG. 6 may be an embodiment of possible combinations of various relay meshes 100 .

Referring to FIG. 6 , the power pack 10 may be connected to a SiC MOSFET 410 , and the SiC MOSFET 410 may be connected to a load 500 through an external connector 30 . The load 500 may be an electric vehicle.

The SiC MOSFET 410 may be connected to the positive (+) terminal and the negative (-) terminal of each power pack 10 of the plurality of power packs 10, respectively,

The positive (+) terminal of the first power pack 11 may be connected to the first SiC MOSFET 411 , and electricity may be supplied from the first SiC MOSFET 411 to the load 500 . Similarly, the positive (+) terminal of the second power pack 12 may be connected to the second SiC MOSFET 412 , and electricity may be supplied from the second SiC MOSFET 412 to the load 500 .

The negative (-) terminal of the first power pack 11 may be connected to the third SiC MOSFET 413 , and electricity may be supplied from the load 500 to the third SiC MOSFET 413 . Similarly, the negative (-) terminal of the second power pack 12 may be connected to the fourth SiC MOSFET 414 , and electricity may be supplied from the load 500 to the fourth SiC MOSFET 414 .

Electricity passing through each SiC MOSFET may be combined by nodes and supplied to the load 500 , and electricity passing through the load 500 may be divided by nodes and supplied to each SiC MOSFET. For example, electricity passing through the first SiC MOSFET 411 may meet electricity passing through the second SiC MOSFET 412 at the first node N1 and supplied to the load 500 . Similarly, electricity from the load 500 may branch and flow from the second node N2 to the third SiC MOSFET 413 and the fourth SiC MOSFET 414 .

When the first SiC MOSFET 411 is turned on and the third SiC MOSFET 413 is turned on, it is a normal mode in which electricity from the first power pack 11 can be supplied to the load 500 . can do. Similarly, when the second SiC MOSFET 412 is turned on and the fourth SiC MOSFET 414 is turned on, electricity of the second power pack 12 can be supplied to the load 500 . You can call it a mod.

For example, when only electricity from the first power pack 11 is required to be supplied to the load 500 , the first SiC MOSFET 411 is turned on and the third SiC MOSFET 413 is turned on. When the second SiC MOSFET 412 and the fourth SiC MOSFET 414 are turned off, electricity from the first power pack 11 may be normally supplied to the load 500 . However, if the third SiC MOSFET 413 fails or a problem occurs, the third SiC MOSFET 413 will be turned off, and the fourth SiC MOSFET 414 may be turned on instead, This may be referred to as a standby mode. Similarly, when only electricity from the second power pack 12 is required to be supplied to the load 500, the second SiC MOSFET 412 is turned on and the fourth SiC MOSFET 414 is turned on, When the first SiC MOSFET 411 and the third SiC MOSFET 413 are turned off, electricity from the second power pack 12 may be normally supplied to the load 500 . However, if the fourth SiC MOSFET 414 fails or a problem occurs, the fourth SiC MOSFET 414 will be turned off, and the third SiC MOSFET 413 may be turned on instead, This may be referred to as a standby mode. That is, the fourth SiC MOSFET 414 may be a spare SiC MOSFET of the first power pack 11 , and the third SiC MOSFET 413 may be a spare SiC MOSFET of the second power pack 12 .

Accordingly, the SiC MOSFET connected to the negative (-) terminal of each power pack 10 may perform a preliminary role in preparation for a failure or defect with respect to the SiC MOSFET connected to the positive (+) terminal.

In addition, even in the normal mode in which the SiC MOSFETs connected to the positive and negative terminals of each power pack 10 are turned on, the administrator can Compared to the case where SiC MOSFETs are connected one by one, control is easier because two SiC MOSFETs are used to obtain the desired PWM (Pulse Width Modulation).

10... Power Pack 11... 1st Power Pack
12... 2nd power pack 20... Control unit
30... External connector 32... Control board
40... display unit 100... relay mesh
200... SiC module 300... SiC drive module
301... first SiC drive module 302... second SiC drive module
303... Third SiC drive module 304... Fourth SiC drive module
310... digital isolator 311... first digital isolator
312... second digital isolator 313... third digital isolator
314... Fourth digital isolator 320... Charge pump
321... first charge pump 322... second charge pump
323... Third charge pump 324... Fourth charge pump
400... SiC MOSFET module 410... SiC MOSFET
411... 1st SiC MOSFET 412... 2nd SiC MOSFET
413... 3rd SiC MOSFET 414... 4th SiC MOSFET
420... heat sink 430... power connector
500... load S10... trigger signal
S20... Status signal S30... Drive signal
N1... first node N2... second node

Claims (9)

an external connector connected to the user's electric vehicle;
a relay mesh for supplying electricity to the external connector; including,
An electric vehicle charging device in which the amount of output power supplied through a relay mesh varies according to the user's choice of fast charging or slow charging.
The method of claim 1,
The relay mesh includes a SiC module,
The SiC module includes a SiC MOSFET module serving as a switch for electricity supplied to the external connector, and a SiC drive module that sends a driving signal for switching to the SiC MOSFET module.
The method of claim 1,
A SiC drive module that sends a driving signal for supplying electricity to the external connector is provided,
In the SiC drive module,
An electric vehicle charging device comprising: a digital isolator that physically separates the SiC drive module from other circuits; and a charge pump serving as a DC-DC converter.
The method of claim 1,
A SiC MOSFET module for supplying electricity to the external connector through switching is provided,
In the SiC MOSFET module,
A heat sink for lowering heat loss generated in the SiC MOSFET module, a power connector to which electricity supplied to the external connector is connected, is turned on when electricity is supplied to the external connector, and is off when not supplied. ) is equipped with a SiC MOSFET,
The SiC MOSFET is an electric vehicle charging device using silicon carbide (SiC) as a material of a semiconductor device.
The method of claim 1,
A display unit is provided for the user to select rapid charging or slow charging,
The signal according to the selection is sent to the control board, and the control board sends an operation signal to the external connector and the control unit selected by the user,
The control unit sends a trigger signal to the relay mesh according to the operation signal to control the amount of power transmitted to the external connector.
The method of claim 1,
A first SiC module and a second SiC module are provided in the relay mesh,
A power pack for supplying DC electricity for charging an electric vehicle to the first SiC module and the second SiC module is provided;
An array SiC module in which the first SiC module and the second SiC module are connected in parallel is provided;
In response to a trigger signal from a control unit, the array SiC module outputs a positive integer multiple of the amount of power output from each SiC module.
The method of claim 1,
A plurality of power packs that supply DC electricity for charging electric vehicles are provided to the SiC module,
SiC MOSFETs are respectively connected to the positive (+) and negative (-) terminals of the power pack,
An electric vehicle charging device in which PWM control is fed back by the plurality of SiC MOSFETs.
The method of claim 1,
A plurality of power packs that supply DC electricity for charging electric vehicles are provided to the SiC module,
The positive (+) terminal of the first power pack is connected to a first SiC MOSFET, and electricity is supplied from the first SiC MOSFET to the load;
The positive (+) terminal of the second power pack is connected to a second SiC MOSFET, and electricity is supplied from the second MOSFET to the load;
The negative (-) terminal of the first power pack is connected to a third SiC MOSFET, and electricity is supplied from the load to the third SiC MOSFET;
The negative (-) terminal of the second power pack is connected to a fourth SiC MOSFET, and electricity is supplied from the load to the fourth SiC MOSFET;
The electricity passing through the first SiC MOSFET and the second SiC MOSFET is combined at a first node and supplied to the load,
The electricity passing through the load is branched from the second node and supplied to the third SiC MOSFET and the fourth SiC MOSFET,
When the first SiC MOSFET and the third SiC MOSFET are turned on and electricity of the first power pack is supplied to the load, or the second SiC MOSFET and the fourth SiC MOSFET are turned on and the second An electric vehicle charging device that sets a normal mode when electricity from a power pack is supplied to the load.
The method of claim 1,
A plurality of power packs that supply DC electricity for charging electric vehicles are provided to the SiC module,
The positive (+) terminal of the first power pack is connected to a first SiC MOSFET, and electricity is supplied from the first SiC MOSFET to the load;
The positive (+) terminal of the second power pack is connected to a second SiC MOSFET, and electricity is supplied from the second MOSFET to the load;
The negative (-) terminal of the first power pack is connected to a third SiC MOSFET, and electricity is supplied from the load to the third SiC MOSFET;
The negative (-) terminal of the second power pack is connected to a fourth SiC MOSFET, and electricity is supplied from the load to the fourth SiC MOSFET;
The electricity passing through the first SiC MOSFET and the second SiC MOSFET is combined at a first node and supplied to the load,
The electricity passing through the load is branched from the second node and supplied to the third SiC MOSFET and the fourth SiC MOSFET,
When a defect occurs in the third SiC MOSFET, a case in which the first SiC MOSFET and the fourth SiC MOSFET are turned on and the third SiC MOSFET is turned off is a preliminary mode;
In the spare mode, the SiC MOSFET connected to the negative terminal of the power pack becomes a spare MOSFET of the SiC MOSFET connected to the negative terminal of another power pack.

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